Process of separating mineral oils



May 28, 1935. H. T. BENNETT PROCESS 0F SEPARATING MINERAL OILS Filed June 23, 1935 5 WN vm m Hrrokwfr.

Patented May 28, 1935 UNITED sTATEs 3 y 2,003,238 v PRocEss oF SEPARATING MINERAL oms Y Harry T. Bennett, Tulsa, Okla., assignerv to Mid- Continent Petroleum Corporation, Tulsa, Okla., a corporation of Delaware f Application June 23, 1933, Serial No. 677,257

6 Claims.

This invention relates to processes of separating mineral oils whereinl selective solvents are employed to effect the desired separation. This application is a continuation in part of an application Serial No. 519,698, filed by me on March 2, 1931.

Mineral oils, including petroleum, and-especially the lubricating fractions of petroleum oil, consist largely of paraiiinic and .naphthenic portions which may be 4separated from each other by commingling the oil with a suitable selective solvent, and thereafter permitting the mixture to settle into layers, or otherwise separating the selected portion from the other portion ofthe oil.

Various advantages may be gained in the use of such solvents to improvethe quality of lubricating oil by removing the paraifinic Wax, or by removing valuable .vparaiiinic lubricating o'il from naphthenic portions of the oil.

Numerous selective solvents have been suggested for work of this kind, and in my own work, I have met with an vexceptional degree of success in the use of a solvent having an odor which would be objectionable in the finished products. An advantage is gainedfby completely eliminating this o dorffrom the products,l even though itV may not impair their functions, and aside from the odor, it is desirable to entirely remove any residual portion of the solvent diffused inthe products.

`One of the objects oi the present invention is to provide a highly eflicient method of removing the solvents from the products. More specifically stated, an object is to remove the minute residual portions of solvent whichv are objectionable on account of theirodor, or because they reduce the efficiency of the products.

A further object is to utilize selective solvents 40 having the various properties most desirable for commercial separation of mineral oils into naphthenic and parafnic fractions, such solvents including ethers, and the like, having an odor' which should be removed-from the products, as well as other solvents which become so united with the products that they cannot be completely, or conveniently, removed by `the methods heretofore employed ,inthe use of such selective solvents. l 3 Y a For example, in one form of the invention, I produce `high viscosity index lubricating oils highly resistantV to oxidation, or sludging, and having a low carbon-forming tendency, by using an ethery as a selective solvent to separate the original oil into paraiilnic and naphthenic (Cl. ISG-13) fractions. Approximately all of the solvent can be veryreadily distilled from vthese fractions, and by a special method of distillation, I have succeeded in removing practically all traces-of the solvent, aside from an infinitesimal diil'used 5 portion which imparts a slight odor to theoil, This odor is perceptible to one skilled in the art, and has been found objectionable-in the high gradelubricating oils produced by the use of an ethereal selective solvent. f 10 However, in accordance with the present'invention, the numerous commercial `advantages of such solvents, including BB dichlorethyl ether, can be obtained in the separation` of mineral oils, and after theseparated solutions 15 have been distilled to recover approximately all ofthe solvent, eitherproduct can be subjected to the deodorizing operation hereinv disclosed, with the result of removing extremely minute particles of solvent diffused inthe oil.

With the foregoingand other objects in` view, the invention comprises the novel method, construction, combination and arrangements of parts hereinafter more specifically described and shown in .the accompanying drawing, which 25 illustrates one form, Aof the invention.. -However, it is tobe` understoodvthat the invention comprehends changes, variations and modications which come within the scope of the claims hereunto appended.

In the preferred form ofthe invention BB dichlorethyl ether is employed as the selective solvent, but other halogenated ethers may be used, and some of the advantages of the present invention may be obtained in using various other solvents including nitrobenzene, phenol, aniline, cresol, yfurfurol, crotonic aldehyde, di chlorethylene, trichlorethylene,v etc. i To aidvin describing one lform oi the inven tion, I will refer to the accompanying drawing, 40 which is a diagrammatical view of an apparatus adapted for use in carrying out the invention.

The oil to be treated passes from a receptacle I, through a pipe 2, toga mixer 3. The selective solvent flows from a receptacle I, through a pipe 5, to the lsame mixer 3.l Y

The solvent and oil, after being agitated in the mixer 3, are discharged through a pipe 6 to a separator l, Where the parainic andnaththenic portions gradually separate into layers in contact with each other. The parainic portion, with any solvent carried therein,` isdischarged through a pipe 8 .to a still! provided with a vapor line I0 leading to a condensenli which discharges into a tank I2,

The naphthenic solution discharged from the separator 1, likewise passes through a pipe i3 leading to a still |4 provided with a condenser I5 discharging into a tank i6. Y

The solutions in the stills 9 and i4 are preferably subjected to distillation under a vacuum, and a large portion of the solvent will berfreely vaporized and discharged to the condensers, without injecting steam into the stills. However, as the distillation progresses, steam or inert gas may be introduced through pipes i1 and i8, respectively, to remove approximately all of the solvent from the oil fractions.

The water and solvent discharged from the condenser flow into the tank i2 where they may be permitted to settle by gravity. This' vstations including the stills 9 and i4, and the return pipe 2| leading back to the solvent receptacle 4.

Approximately all of the solvent is removed from the oil fractions in the stills 9 and i4, but in commercial practice a small quantity of the solvent usually remains in these oil fractions after the distilling operation; I will now describe details of a specific method whereby any objectionable residual solvent can beremoved from one or both of the oil fractions, with the understanding that the scope of the invention is to be determined by the claims, and not by'this specific description of details.

In the manufacture of high viscosity index lubricating oils, the objection, to any indication of solvent in the parafilnic product would usually be greater than the objection to solvent in the naphthenic product. f

Therefore, in the preferred form of the invention, the paraiilnic fraction is discharged from the still 3 through a pipe 24 leading'to a refining station, where the presence of any objectionable solvent is eliminated from this fraction. 4 1

The naphthenic iractionis discharged from' the still 4 through a pipe 25 leading to a tank 26, and if desired, this fraction maybe transmitted to the above mentioned refining station as suggested by a valved pipe 21 leading from the pipe 25 to the pipe 24. In other words, either, or bot-h, of these' fractions may be treated to completely eliminate the presence of objectionable solvent therein.

To illustrate this feature,Ilhave shown a'relning station, or deodorizing station, including a receptacle 23 adapted to communicate -with the pipe 24, said receptacle being provided with a pipe 2S through which live steam, or other gaseous fluid is injected into the oil. The contents of the receptacle 23 arepreferably-subjectedv to a high temperature, for example, above 200 F., and also subjected to agitation while the gaseous iluid is discharged from the pipe 29. The residual solvent is thus removed from the oil and carried out through a discharge pipe 30 extending from the top of the receptacle 28.

This -operation of removing the solvent and its odor can be conveniently performed in a contacting kettle wherein the hot oil is cornmingled with a suitable adsorbent or absorbent material.

VFor example, in the drawing I have shown an acid agitator 3| connected to the pipe 24, a pipe 32 connecting said acid agitator to the kettle 28, a discharge pipe 33 leading from said kettle to a lter press 34, and a pipe 35 connecting the filter press to a tank 33. The acid-treatment may be dispensed with by transmitting the oil through a valve-controlled by-pass 31 connecting the pipe 24 to the pipe 32.

As a very specific example, I will state that the oil in the acid agitator 3| may be treated with a small quantity of 93% or 98% sulphuric acid, using about A to l/2 pound of acid for each barrel of oil. This acid-treated oil is transmitted through pipe 32 to the kettle 28 where it may be commingled with a finely divided absorbent, or adsorbent, material such a fuller's earth, and subjected to a temperature of approximately 260 F. to 350 F., while undergoing agitation in the kettle.

To remove the small quantity of solvent which may impart an objectionable odor to the oil, live steam may be introduced through the pipe 29 for a period oi about ten to thirty minutes.

The contents of the kettle 23 are eventually discharged through the pipe 33 to the illter 34 which removes the adsorbent material, while the deodorized oil passes on through the pipe 35 to the tank 36. l

As a speciilc example, I will state that, after being subjected to an ordinary acid and clay treatment, a Mid-Continent. lubricating oil having a gravity of 26.4 Baume, a iiash point of 405 F., a viscosity of 255 at 100 F., and a viscosity, index of 75, may be mixed with BB' dichlorethyl ether in the mixer 3 at a temperature of about 80 F. to 105 F. This mixture may consist of about two parts of the ether to one part of the oil. The same temperature may be maintained in the separator 1 where the naphthenic and parafilnic fractions gradually separate from each other. The lubricating oil in the material discharged through the pipe 8 is more paraillnic than the original oil, and it has a considerably higher viscosity index than said original oil. The material discharged through pipe I3 is a solution containing a lubricating oil more naphthenic than saidoriginai oil, and the viscosity index of this naphthenic lubricating oil is lower than that of the original oil.

The temperature in the vacuum stills 9 and i4 may be about 280 F. during the iirst part of the run, and it is desirable to thereafter increase this temperature to about 330 F. while introducing live steam through the pipes i1 and i3. This will ordinarily remove any vsubstantial trace oi' the solvent, aside from a minute diffused portion, which may impart a perceptible odor to the oil, but any objection to this odor canbe eliminated by the subsequent operation whereby the diffused solvent is removed from the product.

To simplify the illustration, I have shown a single separating chamber 1, but it is to be understood that the parafnic fraction of the oil may be subjected to successive mixing and separating operations, using additional quantities of fresh solvent; or the naphthenic solution resulting from one separating operation may be used in preliminary mixing and separating operations, so as to remove some of the naphthenic portions-from the original oil before it is subjected to the treatment with fresh solvent.

It is, of course, understood that suitable valves and pumps will be employed to emciently control the transmission of the several fluids from one station tc another, and a complete commercial system will include numerous other details not shown in the accompanying drawing. However, this drawing is merely a diagrammatical illustration of one form of the invention, and in view of the foregoing disclosure, such details will be apparent to those skilled in the art. Furthermore, the invention extends to various modifications within the scope of the terms employed in the following claims.

I claim:

1, In the art of using selective solvents to separate lubricating oil into fractions more parailinic and less parailinic than the original oil, the process which comprises commingling the oil with chlorinated ether, thereafter separating the selected fraction from the other fraction, distilling from the more paraffinic fraction approximately all of the'chlorinated ether contained therein, and thereafter subjecting said parafnic fraction to a deodorizing operation whereby the ether odor is removed from the paraiiinic ol.

2. 'Ihe process of separating lubricating oil into fractions more paralnic and less parafilnic than the original oil, which comprises commingling the lubricating oil stock with dichlorethyl ether, separating said fractions from each other, distilling from the more paraflinic'oil approximately all of the dichlorethyl etherv contained therein, and thereafter subjecting said paraiiinic oil to a deodorizing operation whereby the odor of dichlorethyl ether is removed.

3. The process of .separating lubricating oil into fractions more parainic and less parafnic than the original oil, which comprises commingling the lubricating oil stock with dichlorethyl ether, separating said fractions from each other, distilling from the more parailinic oil approximately all of the dichlorethyl ether contained therein, and thereafter subjecting said paramnic oil to a deodorlzing operation whereby the odor of dichlorethyl ether is removed, said deodorizing operation including the step of subjecting the odorous paraiiinic oil to a high temperature and at the same time injecting a gaseous fluid into the heated material.

4. The process of separating lubricating oil into fractions more paraflinic and less paraffinic than the original oil, which comprises commingling the lubricating oil stock with dichlorethyl ether, separating said fractions from each other, removing from the more parailinic oil approximately all of the dichlorethyl ether contained therein, thereafter agitating said paratlinic oil at a temperature above 200 F., and at the same time removing the odorous trace of ether from the treated oil by injecting a gaseous fluid into the heated material.

`5. The process of separating lubricating oil into fractions more `paraillnic and less parafnic than the original oil, which comprises cornmingling the lubricating oil stock with dichlorethyl ether, thereafter separating said fractions from each other, distilling from the more paraiiinic fraction approximately all of the dichlorethyl ether contained therein, `while injecting steam into the liquid undergoing distillation, removing said parafllnic fraction from the still, treating it with sulphuric acid, commingling the treated paraifinic oil with finely divided earth at a temperature above 200 F., and at the same time removing the odorous trace of ether from the treated oil by injecting live steam into the heated mixture.

6. In the art of using selective solvents to separate lubricating oil into fractions more paraffinic and less paraflinic than the original oil, the process which comprises commingling the oil with BB' dichlorethyl ether, thereafter separating the selected fraction from the other fraction, distilling from the more parailnic fraction approximately all of the BB dichlorethyl ether contained therein, and thereafter subjecting said parailinic fraction to a deodorizing operation whereby the ether odor is removed from the parainic oil.

HARRY T. BENNETT. 

